An arrangement in which when assembling a power storage module by connecting a pair of end plates superimposed at opposite ends in the stacking direction of a plurality of stacked power storage cells by means of a restraining band (frame) made of metal, the formation of a liquid junction between the power storage cells and a vehicle body via the frame is prevented by disposing a tray, made of an insulating body, between the power storage cells and the frame is known from Patent Document 1 below.